Vendor dependencies

Let's see how I like this workflow.

vendor/thiserror/tests/ui/lifetime.rs

@@ -0,0 +1,24 @@
+use std::fmt::Debug;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+#[error("error")]
+struct Error<'a>(#[from] Inner<'a>);
+
+#[derive(Error, Debug)]
+#[error("{0}")]
+struct Inner<'a>(&'a str);
+
+#[derive(Error, Debug)]
+enum Enum<'a> {
+    #[error("error")]
+    Foo(#[from] Generic<&'a str>),
+}
+
+#[derive(Error, Debug)]
+#[error("{0:?}")]
+struct Generic<T: Debug>(T);
+
+fn main() -> Result<(), Error<'static>> {
+    Err(Error(Inner("some text")))
+}